Many baked goods, such as rolls, cookies, pizzas, etc., are baked on cookware or bakeware, such as baking sheets. The bakeware can be flat, such as a baking sheet, or can be shaped, such as bakeware containing domed portions or cavities. Typically, the bakeware as described above have a relatively small thickness in relation to surface area. Many of the above bakeware products, for instance, can have a size of 600 mm×400 mm, 600 mm×800 mm, or, for instance, 800 mm×1000 mm.
Conventional cookware and bakeware products have been made from metals. For example, aluminum, copper, cast iron and stainless steel have all been used to produce the above described products. Metal cookware, for instance, is strong and resistant to breaking and conducts heat very well.
Food stuffs, however, have a tendency to stick to metal surfaces. In order to remedy this problem, modern metal cooking pans and baking pans are frequently coated with a substance in order to minimize the possibility of food sticking to the surface of the utensil. Coatings that have been used in the past include polytetrafluoroethylene (PTFE) or silicone. Such materials, for instance, have been used to coat not only commercial and consumer products, but are also used in many industrial settings, such as industrial bakeries and other food processing plants. Although these coatings can deliver non-stick properties, unfortunately the coatings have a tendency to break down, peel off and degrade over time requiring either replacement or periodic recoating of the metal cookware and bakeware. In addition, the process for producing polytetrafluoroethylene has recently come under scrutiny due to possible health hazards related to various components used to produce the product.
In addition to the above, metal bakeware tends to be relatively heavy and can corrode. In addition, metal bakeware produces loud and noisy sounds when handled. Further, metal sheets can also bend when handled improperly or when dropped.
in the past, those skilled in the art have investigated the use of non-metallic materials to manufacture cookware and bakeware products. For example, U.S. Pat. No. 4,626,557 and U.S. Pat. No. 5,132,336, which are incorporated herein by reference, describe various plastic compositions which can be fabricated into permanent ovenware capable of repeated use in both conventional thermal and microwave ovens. The plastic material is comprised of a wholly aromatic polyester resin that inherently possesses good anti-stick properties that is readily releasable from the food which it contacts. Other patent applications and patents that describe the use of liquid crystal polymers for producing bakeware and cookware are described in U.S. Patent Application Publication No. 2006/0014876, U.S. Patent Application Publication No. 2005/0199133, U.S. Pat. No. 7,540,394, U.S. Pat. No. 6,942,120, U.S. Pat. No. 5,141,985, U.S. Pat. No. 4,922,811, and U.S. Pat. No. 4,741,955, which are also all incorporated herein by reference.
Although various advantages and benefits can be obtained by constructing cookware and bakeware from aromatic liquid crystal polymers, various drawbacks still remain. For instance, in the past, the cookware that contained aromatic liquid crystal polymers was formed through an injection molding process. Although injection molding is an effective way for producing some cookware products, injection molding is generally not satisfactory for producing cookware products that have a large surface area in relation to thickness. Injection molding large-area, planar structures, for instance, can lead to tensions in the molded part, due to the processing speed. For example, when filling large and relatively thin-walled molds using injection molding, high injection pressures are required that unavoidably create high residual stress which can cause warpage of the part or the formation of blisters. In the past, attempts have been made to reduce stress by using multiple injection points on the mold. Using multiple injection points, however, creates seams which form weak points in the resulting product.
In this regard, the present disclosure is directed to an improved process for producing three-dimensional products. As will be described in greater detail below, the process of the present disclosure is particularly well suited for producing three-dimensional products that have large planar surfaces at relatively low thicknesses.